Relationship between Biochemical Bone Markers and Bone Mineral Density in Patients with Phenylketonuria under Restricted Diet.

OBJECTIVE: Most of phenylketonuria (PKU) develops bone turnover impairment and low bone mineral density (BMD). Measurements of BMD reflect only bone mineral status but not the dynamics of bone turnover. Bone markers are a noninvasive tool useful for the assessment of bone formation and bone resorption processes. Our study was to assess the levels of bone markers in PKU in order to select a screen marker and detect the most specific marker which can be combined with BMD for appropriate follow up. METHODS: Thirty three classic PKU patients were studied. BMD and bone mineral content (BMC) were measured. Total alkaline phosphatase (ALP), osteocalcin (OC) and carboxy-terminal propeptide of type I collagen (CICP), osteoprotegerin (OPG), receptor activator of nuclear factor κß ligand (RANKL) and Deoxypyridinoline (DPD) were measured. Findings : Nineteen (57.6%) male and fourteen (42.4 %) female PKU patients were involved in the current study. Their mean age was 8.4±4.6 yrs and the age range 3-19 yrs. The control group consisted of twenty two (52.4%) males and twenty (47.6%) females. Their mean age was 8.5±3.3 yrs and th age range 2-17 yrs. Using the Z score values, there was a significant decrease of total BMC (TBMC-Z), BMD of the femoral neck BMD-FN-Z, BMD of lumbar vertebrae (BMD-L-Z), BMD-FN and DPD while RANKL increased. There was a negative correlation between CICP and TBMC and between CICP and BMD-L in these patients. Also, a negative correlation between ALP and TBMC and between ALP and BMD-L was observed. It was concluded that the ALP provides a good impression of the new bone formation in the PKU patients and it has a highly significant negative correlation with the many parameters of the bone mineral status beside the wide availability of inexpensive and simple methods. So a screening test and/or follow up for the PKU patients using ALP would be available. Once the level of ALP decrease is detected, one can combine it with BMD to explore the bone mineral status and with specific bone markers (OC, RANKL and DBD), to verify the dynamics of bone turnover. CONCLUSION: This schedule will reduce the risk of exposure of these patients to the risk hazards of DXA and limit its use only to a limited number of the highly suspected cases.

Mycotoxins and child health: the need for health risk assessment.

The occurrences of mycotoxins as food contaminants in different localities particularly in developing countries and the inevitable exposure of populations and children to these toxins with probable adverse outcomes need be scientifically and systematically assessed. Health risk assessment developed in the 1980s is separate from risk management, both with risk communication form the risk analysis framework adopted by the World Health Organization. The process contributes increasingly to policy development, public health decision making, the establishment of mycotoxin regulations and research planning. However, the exercise of the risk assessment structured approach is not simple and is faced up to lack of data, capable infrastructure facilities and need for trained personnel and resources. Furthermore, adopted methodologies need be developed focusing on child characteristics and health concerns.

The spectrum of inherited bleeding disorders in pediatrics.

Inherited bleeding disorders (IBDs) are caused by quantitative and qualitative alterations of either platelets or plasma proteins involved in coagulation and fibrinolysis. Hemophilias are the most frequent IBDs; however, accumulated data from various studies reported that von Willebrand disease (VWD) is the most common cause of IBD, with an increased incidence of platelet function defects, mostly due to the increased rate of consanguinity in some communities. VWD is an inherited disorder of homeostasis due to quantitative or qualitative defect of von Willebrand factor. Data on its epidemiology and impact in developing countries are limited. The objective of this study was to assess the local prevalence of some IBD and establish the clinical and historical variables that are predictive for those bleeding disorders in pediatrics. The study involved 43 children with various bleeding manifestations and 15 age- and sex-matched controls, recruited from the Pediatrics Hematology Clinic at the National Research Centre, Sausan Mubarek children's hospital in Cairo, Egypt and the King Abdulaziz University Hospital, Jeddah, Kingdom of Saudi Arabia. Hematological profile included platelet counts and function, prothrombin time, partial thromboplastin time, factor VIII antigen and its activity, factor IX antigen and its activity, von Willebrand factor and its activity assayed with multimeric analysis. A total of 12 (27.9%) children had VWD, 11 (25.5%) had hemophilia A, three (7%) had hemophilia B, seven (16.3%) had platelet dysfunction and 10 (23.3%) had bleeding with undiagnosed cause. Two of the VWD cases had type I, three had type II, four had type III and one case appeared to have type IIM and another to have IIB VWD. Bruising and epistaxis were the main symptoms in all children with VWD The majority of platelet dysfunction disorders were diagnosed as Glanzmann's thrombasthenia. VWD and Glanzmann's thrombasthenia should be considered not uncommon causes of IBDs in children in Egypt and Kingdom of Saudi Arabia. Routine hematological screening should be mandatory in children with positive family history of bruising and bleeding as a predictor for IBD.